Cyanine dyes containing a sulfohydrocarbon radical



Patented Apr. 11, 1950 UNITED STATES PATENT OFFICE CYANINE DYES CONTAINING A SULFO- HYDROCARBON RADICAL Robert H. Sprague, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application March 21, 1947, Serial No. 736,405

9 Claims.

This invention relates to cyanine dyes containing a sulfohydrocanbon radical on one or both of the auxochromophoric nitrogen atoms.

Cyanine dyes containinga carboxyalkyl group on one or both of the auxochromophoric nitrogen relative to the cation. The known dyes containing a carboxyalkyl group on each of the two auxochromophoric nitrogen atoms, on the other hand, are distinguished by the fact that they do not consist of a separate cation and an anion bound together by electrostatic attraction, but rather consist of a zwitter ion in which one of the nitrogen atoms of the auxochromophoric group carried a positive charge and a carboxyalkyl group attached thereto is in the form of a negatively charged group owing to the loss of a hydrogen atom from the carboxyl group.

I have now found cyanine dyes in which there is a sulfohydrocarbon radical on one or both of the auxochromophoric nitrogen atoms. These new dyes difier widely in properties from the aforesaid known cyanine dyes containing carboxyalkyl groups. First, my new dyes containing a sulfoalkyl group on but one of the auxochromophoric nitrogen atoms are zwitter ions whereas the cyanine dyes containing a carboxyalkyl group on but one of the auxochromophoric nitrogen atoms contain a separate anion, such as halide, p-toluenesulfonate, etc. Second, my new dyes, generally speaking, do not dissolve in ethyl alcohol containing triethylamine as do the aforesaid zwitter ion dyes containing a carboxyalkyl group. My new dyes, however, sensitize photographic silver halide emulsions.

Since my new dyes contain no separate anion, they cannot be named satisfactorily strictly according to existing systems of nomenclature for cyanine dyes and it has been necessary to devise a special systematic method for naming these dyes. The system can be illustrated with reference to one of my new dyes which can be represented by the following formula:

2 This dye is called anhydro-3,3'-di-;3-sulfoethylthiacarbocyanine hydroxide. In other words, this system of nomenclature regards this dye as the inner anhydride or salt of the hypothetical thiacarbocyanine hydroxide which would be represented by the following formula:

N JH: C OH (5H2 HI 5 0311 80311 This system of nomenclature for these new dyes avoids the danger of confusion with names of known dyes.

It is, accordingly, an object of my invention to provide anhydro sulfohydrocarbon radical cyanine hydroxides. A further object is to provide a process for preparing these new compounds. A still further object is to provide photographic emulsions sensitized with these new compounds. Other objects will become apparent hereinafter.

The anhydro cyanine hydroxides of my invention can be represented by the following general formula:

w'herein d and 11. each represents apositive integer of from 1 to 2, m represents a positive integer of ethylene,

trimethylene, etc., and Z and. Z1 each represents the non-metallic atoms necessary to complete a. heterocyclic nucleus containing from 5 to 6 atoms in the heterocyclic ring, e. g. thiazole, 4-phenylthiazole, 4,5-diphenylthiazole, 4-(2-thienyl) thiazole, 4-methylthiazole, benzothiazole, 4-chlo'robenzothiazole, 4-methylbenzothiazole, 4-methoxygeneral formula I wherein 111. represents 1.

benzothiazoie, 4'-ethoxybenzothiazole, 4-phenylbenzothiazole, 5-chlorobenzothiazole, 5-bromobenzothiazole, S-methylbenzothiazole, 5-methoxybenzothiazole, 5-ethoxybenzothiazole, 5-phenylbenzothiazole, fi-chlorobenzothiazole, 6-bromobenzothiazole, G-methylbenzothiazole, 6-methoxybenzothiazole, 6-ethoxybenzothiazole, 4-phenyloxazole, benzoxazole, 5-chlorobenzoxazo1e, 5- methylbenzoxazole, 5-bromobenzoxazole, 5-methoxybenzoxazole, 5-ethoxybenzoxazole, 5-phenylbenzoxazole, 4-methylselenazole, 4-phenylselenazole, selenazole, benzoselenazole, 5-chlorobenzoselenazole, a-naphthothiazole, p-naphthothiazole, quinoline, G-methylquinoline, 6-methoxyquinoline, 6-ethoxyquinoline, 6-chloroquinoline, 4- methoxyquinoline, 4-methylquinoline, S-methoxyquinoline, l3-methylquinoline, 4-chloroquinoline, 3,3-dimethylindo1enine, etc.

In accordance with my invention I prepare anhydro cyanine hydroxides containing a sulfohydrocarbon radical by condensing a cyclammonium quaternary salt selected from those represented by the following general formula:

wherein R, L, d and Z have the values given above, R1 represents an alkyl group, e. g. methyl, ethyl, n-propyl, n-butyl, isobutyl, benzyl or an aryl group, e. g. phenyl, p-chlorophenyl, rx-naphthyl, etc., and X represents an anion, e. g. chloride, bromide, iodide, benzenesulfonate, p-toluenesul- ,fonate, methylsulfate, ethylsulfate, acetate, propionate, thiocyanate, perchlorate, etc. with a cyclammonium quaternary salt selected from those represented by the following general formula:

wherein L, n, D, X and Z1 have the values given above and R2 represents a hydrogen atom or an alkyl group, e. g. methyl, etc. This condensation gives monomethine anhydro cyanine hydroxides, i. e. anhydro cyanine hydroxides, of the above This condensation is advantageously effected in the presence of a basic condensating agent, e. g. a tertiary organic amine, for instance, pyridine, triethylamine, tri-n-propylamine, tri-n-butyl- .amine, triisoamylamine, dimethylaniline, diethylaniline, etc.

thiazole metho-p-toluenesulfonate, 5-chloro-2 methylmercaptobenzothiazole ethoethylsulfate, 2-methylmercaptobenzoxazole etho-p-toluenesul- ,fonate, 2-methylmercaptobenzoselenazole methop-toluenesulfonate, 2 methylmercapto-fl-naphthothiazole etho-p-toluenesulfonate, 2-methylmercapto-a-naphthoxazole metho p-toluenesulfonate, 2-phenylmercaptoquinoline ethiodide, 2-

,n-butylmercaptoquinoline ethiodide, 2-phenylmercaptopyridine ethiodide, etc.

Typical of the cyclammonium quaternary salts of Formula III are: 5-chloro-2-methylbenzo- .thiazole p-sulfobenzyl bromide, z-methylbenzothiazole p-sulfobenzyl bromide, lepidine p-sulfobenzyl bromide, 5-ch1oro-2-methylbenzothiazolep-sulfoethyl bromide, 2-methyl-a-naphthothiazole-B-sulfoethyl bromide, 2-methylbenzothiazole-B-sulfoethyl bromide, 2,3,3 trim'ethylindolenine ,s-sulfoethyl bromide, etc. Quaternary salts represented by Formula III can be prepared as described in my copending application Serial No. 730,565, filed February 24, 1947.

In accordance with my invention, I prepare unsymmetrical meso-substituted trimethine anhydro cyanine hydroxides, i. e. unsymmetrical meso-substituted anhydro cyanine hydroxides of the above general Formula I wherein m represents 2, by condensing a cyclammonium quaternary salt selected from those represented by Formula III above with a cyclammonium quaternary salt selected from those represented by the following general formula:

wherein R, L, 11, Z and X have the values given above, R3 and R4 each represents an alkyl group, e. g. methyl, ethyl, n-propyl, n-butyl, isobutyl, etc. The condensations are advantageously effected in the presence of a basic condensing agent especially a tertiary organic amine, e. g. pyridine, triethylamine, tri-n-propylamine, trin-butylamine, triisoamyl amine, etc. Quaternary salts represented by Formula IV above are described for example in United States Patents 2,369,657 and 2,369,646, each dated February 20, 1945, in the copending application of Grafton H. Keyes, Serial No. 620,162, filed October 3, 1945, and (where R. represents a carboxyalkyl group) in my copending application Serial No. 730,564, filed February 24, 1947 (now United States Patent 2,481,698, dated September 13, 1949).

I prepare symmetrical trimethine anhydro cyanine hydroxides (substituted in the meso position or not) by condensing a cyclammonium quaternary salt selected from those represented by Formula III above with an ester'of an orthocarboxylic acid, e. g. ethyl orthoformate, npropyl orthoformate, n-butyl orthoformate, ethyl orthoacetate, n-propyl ortho acetate, n-butyl orthoacetate, ethyl orthopropionate, n-propyl orthopropionate, n-butyl orthopropionate, ethyl orthobenzoate, etc. The condensations are advantageously effected in pyridine.

I prepare symmetrical trimethine anhydro cyanine hydroxides substituted in the meso position by condensing a cyclammonium quaternary salt selected from those represented by Formula III above with an ester of a dithiocarboxylic acid, e. g. methyl dithioacetate, ethyl dithioacetate, n-propyl dithioacetate, n-butyl dithioacetate, methyl dithiopropionate ethyl dithiopropionate, n-propyl dithiopropionate, n-butyl dithiopropionate, methyl dithiobenzoate, methyl dithiocyclohexane carboxylate, etc. Advantageously the condensations are eifected in the presence of a basic condensing agent. Organic tertiary amines are advantageously employed, e. g. pyridine, triethylamine, tri-n-propylamine, tri-n-butylamine, triisoamylamine, N-methylpiperidine, N-ethylpiperidine, etc. When the stronger amines, such as triethylamine N-methylpiperidine, etc. are employed, it is advantageous to employ these in a pyridine medium.

Trimethine anhydro cyanine hydroxides can also be prepared by condensing a cyclammonium quaternary salt selected from those represented by Formula- III above with a cyclammonium "butadienyD 5, dimethoxybenzothiazole 'benzothiazole ethiodide, *etc.

awards quaternary salt selected from those represented by the following general formula:

v. R R

Z- n'= L-L 'b-oH=0HN X R wherein R, L, n, X and Z have the values given above, R represents a member selected from the group consisting of a hydrogen atom, an alkyl group (especially methyl or ethyl) and an acyl group (especially acetyl, propionyl or butyryl) and .R6 represents an aryl group, e. g. phenyl,

p-chlorophenyl, petolyl, etc.

Typical of these cyclammonium quaternary salts of Formula V are: .2-fl-acetanilidovinylbenzox-azole ethiodide, 2-p-acetanilidovinylbenz0- thiazole ethiodide, 5-chloro-2-p-acetanilidovinylbenzothiazole ethiodide, 2 .8 acetanilidovinylbenzothiazole metho-p-toluenesulfonate, 2- ,B-acetanilidovinylquinoline ethiodide, 4-5-acetanilidovinylquinoline n-butiodide, 2-,B-acetanilidovinyl-,B-naphthothiazole etho-p-toluenesulfonate, 2-B-acetani1ido-a-naphthothiazole methomethylsulfate, 2-ani1inovinylthiazoline methiodide etc.

These condensations which give the trimethine anhydro cyanine hydroxides are advantageously carried out in the presence of a basic condensing agent (acid-binding agent), e. g. a tertiary amine, especially a tertiary amine having an ionization constant greater than at 25 C., e. g..trialkylamines (triethylamine, tri n-propylamine, tri-nbutylamine, triiso'amylamine, etc.), trihydroxyalkylamines (triethanolamine, tripropanol amine, etc.), N-alkylpiperidines (N-methylpiperidine, N-ethylpiperidine, etc.), and so forth. The condensations are advantageously carried out in a solvent, especially an alcohol, e. g. ethyl, .n-propyl, isopropyl, n-butyl or isobutyl alcohol. Pyridine can also be used as a solvent.

Pentamethine anhydro cyanine hydroxides can be prepared by condensing a cyclammonium quaternary salt selected from those represented by Formula III above with a cyclammonium quaternary salt selected from those represented by the following general formula:

X R5 wherein R, L, n, X and Z have the values given above, R7 represents a member selected from the group consisting of a hydrogen atom and an alkyl group (especially methyl or ethyl) and an acyl group (especially acetyl, propionyl or butyryl), and R8 represents an aryl group, e. g. phenyl. Typical of such cyclammonium quaternary salts are: 4-(4-acetanilido-1,8-butadienyl) quinoline ethiodide, 2 (4 anilino 1,3- butadienyDbenzothiazole ethiodide, 2-(4-anilino-L3- ethiodide, 2-(-anilino-1,3-butadieny1) a. naphthathiazole ethiodide, 2-(i-anilino-1,3-butadienyl)- 5 methoxybenzoselenazole ethiodide, 2-(4 anilino 1,3 butadienyl) 6 methylquinoline ethiodide, 2 (4-anilino-3-methyl 1,3 butadienyl) These condensations are advantageously carried out in the presence of a basic condensing agent and solvent, e. g. the basic'condensing agents and alcohol solvents set forth under Formula V above.

To prepare symmetrical pentameth'ine .dyes of the above general Formula I, I condense at least two molecular proportions'of ;a cyclammonium quaternary salt of Formula III'with one molecular proportion :of 1a :B arylaminoacrolein' 'anil salt,

e. (g. B-ani1inoacrolein 'anil hydrochloride. The

Example 1.Anhydro-3-p3-carbozyethyZ-5,'5'-dichloro-Q-methyl 3" 13 sulfoethylthiacarbocyan'ine hydroxide 1.6 g. (1 mol.) of 3-B-carboxyethyl-5-chloro-2- thioacetylmethylenebenzothiazoline and 1.9 g. (2 mole.) of methyl-p-toluenesulfonate were heated on the steam bath for minutes. 1.0 g. (1 mol.) of 5-chloro-2-methylbenzothiazole-flsulfoethylbromide and 25 cc. of pyridine were added and the mixture boiled under reflux for 10 minutes. The purple reaction mixture was chilled to 0 C. and the crystals collected on a filter. The dye was washed on the filter with acetone and water and dried. The yield of dark red crystals was .3 g., 11 .per cent. After recrystallization from glacial acetic acid (1000 cc. per gram) the dye melted with decomposition at 283-285" C. The yield of purified material was .2 g., 7 per cent. The dye is a sensitizer from 500 to 640 m with maxima at 550 and 630 m in a gelatino-silver-bromiodide emulsion.

Example 2. Anhydro-s-e-carbom ethyz-as' dichloro 9 ethyl-3' 13 sulfoethylthiacarbocyanine hydroxide 1.64 g. (1 mol.) of 3-;3-carboxyethyl-5-chloro- 2thiopropionylmethylenebenzothiazoline and 1.9 g. (2 mols.) of methyl-p-to1uenesulfonate were heated on the steam bath for 90 minutes. 1.9 g. (1 mol.) of 5-chloro-2-methylbenzothiazole-B- sulfoethobromide and 25 cc. of pyridine were added and the mixture boiled under reflux for 10 minutes. The mixture was chilled to 0 C., the dye filtered off and washed on the filter with acetone and water. The yield of dark red crystals was .2 g., 7 per cent. The dye was recrystallized from glacial acetic acid (750 cc. per gram) after which it melted with decomposition at 284-286" C. The yield of purified material was .15 g., 5 per cent. The dye is a sensitizer from 500 to 640 In, with a maximum at 630 m, in a gelatino-silver-bromiodide emulsion.

Example 3.-Anhydro-5'-chl0ro-3-ethyl-3'-flsulfoethylthz'acyanine hydroxide l I czHa CIHAS D37 3.5g. (1 mol.) of 2-ethylmercaptobenzothiazole ethiodide, 3.7 g. (1 mol.) of 5-chloro-2-methylbenzothiazole-,8-sulfoethylbromide and 25 cc. of pyridine were boiledtogether under reflux for 15 minutes. The reaction mixture was cooled, diluted'with 150 cc. of ether and chilled to C. The dye was collected on a filter, washed with absolute ethyl alcohol and dried. The yield of yellow crystals was A g., Q-per cent. After recrystallization from glacial acetic acid (430 cc.- per gram) the dye melted aboye 320 C. The yield of purified material was .35 g., 8 per cent. The dye is a sensitizer to 490 m with a maximum at 465 my in a gelatino-silver-chlorobromiodide emulsion.

Emamz'ile 4.-Anhydro-chloro--1-ethyl-3-,B-sulfoethylthia-2'-cyanine hydroxide 4.37 g. (1 mol.) of 2-phenylmercaptoquinoline etho-p-toluenesulfonate, 3.72 g. (1 mol.) of 5- chloro-2-methylbenzothiazole c sulfoethylbromide and 25 cc. of pyridine were boiled under reflux for 5 minutes. The pink reaction mixture was cooled, diluted'with 150 cc. of ether and the ether solution decanted from the sticky precipitatefThe product was dissolved in 15 cc. of hot methyl alcohol and 5 cc. of glacial acetic acid added. Crystals of dye separated out of the solution at once. The product was collected on a filter, washed on the filter with acetone and water and dried. The yield of brown crystals was .6 g., 13 per cent. After recrystallization from glacial acetic acid the dye melted-above 320 C. The yield of purified red crystals was .5 g., 11 per cent. The dye is a sensitizer from 500 to 550 m with a maximum at 530 my in a gelatinosilver bromiodide emulsion.

Example 5.Anhydro-1-ethyl-3- 8-suljoethylthia-2'-cyanine hydroxide CHO I C2115 zHlsOa- 4.37 g. (1 mol.) of 2-phenylmercaptoquinoline etho-p-toluenesulfonate, 3.4 g. (1 mol.) of 2- methylbenzothiazole-fi-sulfoethobromide and 25 cc. of pyridine were boiled together under reflux for 5 minutes. The reaction mixture was cooled, diluted with 150 cc. of ether and the ether solution decanted from the precipitate. The product was dissolved in'15 cc. of hot methyl alcohol and 5 cc. of glacial acetic acid added. Crystals of dye separated out of the solution at once. The product was collected on a filter, washed on the filter with acetone and water and dried. The yield of brown crystals was .2 g., 5 per cent. After recrystallization from glacial acetic acid (200 cc. per gram) the product was .175 g., 4 per cent. The dye is a sensitizer from 500 to 550 m with a maximum at 530 m in a gelatino-silver-bromiodide emulsion.

Example 6.Anhydro-1 -ethyl-1 -p-sulfobenzyl- 2,4-cyanine hydroxide 2.2 g. (1 mol.) of 2-phenylmercaptoquinoline etho-p-toluene-sulfonate, 1.97 g. (1 mol.) of lepidine-p-sulfobenzylbromide, 1.0 g. (2 mols) of triethylamine and 25 cc. of absolute ethyl alcohol were boiled together under reflux for 30 minutes. In order to facilitate the reaction 15 cc. of water was added after 10 minutes of heating. The purple reaction mixture was chilled, to 0 C. and the product collected on a filter. The dye was washed on the filter with acetone and water and dried. The crude product was recrys tallized several times from 50% methyl alcohol (2000 cc. per gram). The yield of purified material was .1 g., 4%. The pure dye was obtained as green crystals which melted at 305-308 with decomposition. The dye is a sensitizer from 550-600 m l with a maximum at 580 my in a gelatino-silver-bromiodide emulsion.

Example 7.Anhyclro 3 ethyl 1-p-sulfobenzyZthz'a-at' -cyam'ne hydroxide OzHs 1.76 g. (1 mol) of 2-ethylmercaptobenzothiazole ethiodide, 2.0 g. (1 mol) of lepidine-p-sulfobenzyl bromide, 1.0 g. (2 mols) of triethylamine and 25 cc. of absolute ethyl alcohol were boiled together under reflux for 30 minutes. After 10 minutes heating 15cc. of water was added to the reaction mixture. The dye was isolated in the same manner as Example 6 and recrystallized from 50% methyl alcohol (2000 cc. per gram). The yield of purified material was .2 g., 8.5%. The pure dye was obtained as red crystals which melted above 320 C. The dye is a sensitizer from 500 to 570 m with a maximum at 530 m in a gelatino-silver-bromoiodide emulsion.

Example 8.Anhydro-5,5-dichloro 3,3'-dz-fisulfoethylthiacarbocyanlne hydroxide pyridine salt N i/ (E2H4SO3H.C5H5N H zHqSOa I 1.86 g. (2 mols) of 5-ch1oro-2-rnethylbenzothiazole-fi-sulfoethylbromide, 1.5 g. (4 mols) of ethylorthoformate and 15 cc. of pyridine were boiled together under reflux for 10 minutes. Crystals of dye separated out rapidly from the boiling reaction mixture. The mixture was chilled to 0 C., the dye collected on a filter and washed on the filter with acetone and water. The product was recrystallized from methyl alcohol cc. per gram). The yield of purified material was .1 g., 6%. The pure dye was obtained as minute green crystals with a bright reflex. The dye melted above 320 C. The dye is a sensitizer from 500 to 620 m with a maximum at 600 m in a gelatino-silver-bromoiodide emul- Example 9.-Anhydro-5,5-dichZoro-9-ethyl-3,3'-

di-fi-sulfoethylthiacarbocyanine hydroxide l I 0211450311 C H SO3" Coppery crystals of dye separated out of the solution on chilling. The dye was collected on a filter, washed on the filter with acetone and water and dried. The yield of dye was .2 g., 13%. The dye was recrystallized from methyl alcohol (250 cc. per gram) The yield of purified material was .1 g., 7%. The dye melted above 300 C. The

dye is a sensitizer from 500 to 660 In with a maximum at 640 m, in a gelatino-silver-bromoiodide emulsion.

Example 10.Anhydro 5,5' -dz'chloro9-methyl- 3,3-di-p-sulfoethylthiacarbocyanine hydroxide ozHls sH 32 43 3 12.4 g. (2 mols) of :-chloro-2-methylbenzothiazole ii-sulfoethyl bromide, 3.5 g. (2 mols) of methyldithioacetate, 3.3 g. (2 mole) of triethylamine and 40 cc. of pyridine were boiled together under reflux for minutes. The reaction mixture was cooled to room temperature, poured into 500 cc. of 10% acetic acid and chilled to 0 C. The product was collected on a filter, washed on the filter with water and dried. The product was recrystallized from methyl alcohol (600 cc. per gram of dye). The yield of purified material was .5 g., 5%. The dye was obtained as purple crystals which melted above 310 0. The

dye is a sensitizer from 500 to 650 m with a maximum at 640 m in a gelatino-silver-bromoiodide emulsion.

Example 11.Anhydro-5,5'-dichloro 3,3'-di-psulfobenzylthiacarbocyanine hydroxide 9.0 g. (2 mols) of 5 -chloro-2-methylbenzothiazole p-sulfobenzylbromide, 6.0 g. (4 mols) of ethylorthoformate and 75 cc. of pyridine were boiled under reflux for minutes. The reaction mixture was cooled to room temperature and the pyridine .decanted off from the sticky precipitate. 50 cc. of 10% alcoholic hydrochloric acid was added to the precipitate whereupon crystals crystals was .35 g., 9%.

of dye separated at once. The product was collected on a filter, washed on the filter withmethyl alcohol and water and dried. The yield of dark green crystals was 2.1 g., 28%. The product was purified by solution in hot methyl alcohol plus triethylamine (500 cc. per gram of dye) and precipitation from the cooled, filtered solution with acetic acid. The yield of purified material was The dye was obtained as bronze crystals which melted above 310 C. The dye is a sensitiz'er from 500 to 620 m with a maximum at 600 m in a gelatino-silver-bromide emulsion.

Example 12.-Anhydro-3-ethyl-1 '-p-sulfobenzylthia-4-carbocydnine hydromide bf V 2.0 g. (1 mol) of 2-,B-acetanilidovinylbenzothiazole ethiodide, 2.0 g. (1 mol) of lepidine 'p-sulfo benzylbromide, 1.0 g. (2 mols) of triethylamine and cc. of absolute ethyl alcohol were boiled together under reflux for minutes. The reaction mixture was chilled to 0 C'., filtered and the product Washed on the filter with acetone and water. The crude product was recrystallized from acetic acid (600 cc. per gram). Theyield of purified material was .65 "g 20%. The purified dye was obtained as dull blue crystals which melted at 278-281 C. with decomposition. The dye is a sensitizer from 630 to 690 mp with a maximum atw670 m in a gelatino-silver-bromoiodide emulsion.

Example 13.Anhydro 5,5'- dichZor0-3,3'- di-psulfobeneylthiadicarbocyanine hydroxide 4.0 g. (2 mols) of 5-chloro-2-methylbenzothi'azole p-sulfobenzyl bromide, 1.3 g. (1 mol) of B- 'anilinoacrolein anil hydrochloride, 2.0 g. (4 mols) of triethylamine and 25 cc. of pyridine were boiled together under reflux for 3 minutes. .Green crystals ofdye separated out rapidly from the boiling reaction mixture. The mixture waschilled to 0 C., filteredand the product washed on the filter with methyl alcohol. The yield" of green The dye was. recrystallized from 50% acetic acid (1400 cc. per gram).

The yield of purified material was .1 g., 3%. The pure dye melted above 310 C. The dye is a sensitizer in a gelatino-silver-bromoiodide emulsion.

Example 14.-Anhydro -.1' ethyZ-W-methomy-5- 2.25 g. (1 mol) of 2-methyl-5-phenylbenzothiazole and 1.9 g. (1 mol) of 2-bromoethanesulfonic acid were heated together in a test tube at 210- 215 C. for two minutes. The brown mixture was cooled and 4.7 g. (1 mol) of 6-methoxy-2-phenylmercaptoquinoline etho-p-toluenes-ulfonate and 20 cc. of pyridine were added. The mixture was boiled for 5 minutes with stirring. The solution was poured into 50 cc. of cold water, the dye filtered off, washed n the filter with water and dried. The yield of brown crystals of dye was 2.3 g., 44%. After recrystallization from 150 cc. of 95% pyridine the dye was obtained as orange crystals which melted above 310 C. The yield of purified dye was .3 g., 6%. The dye is a sensitizer to 580 m with a maximum of 540 my. in a gelatino-silver-bromoiodide emulsion.

The 3-fi-carboxyethyl-5-chloro-2-thioacetylmethylenebenzothiazoline and the 3-;3-carboxyethyl-fi-chloro- 2 thiopropionylmethylenebenzothiazoline employed in Examples 1 and 2 above are described in my copending application Serial No. 730,564, filed February 24, 1947 (now United States Patent 2,481,698, dated September 13, 1949), and are prepared by condensing 5-chloro- 2 methylbenzothiazole p-carboxyethiodide with methyl dithioacetate in the presence of triethylamine in a pyridine medium, and 'by condensing 5-chloro-2-methylbenzothiazole fi-carboxyethiodide with methyl dithiopropionate, in the presence of triethylamine in a pyridine medium.

The quaternary salts represented by Formula III are described in my copending application Serial No. 730,565, filed February 24, 1947. The following examples illustrate the preparation of these quaternary salts.

Example 15.-5-chloro-Z-methylbenzothiazole psulfobenzyl bromide 18.4 g. (1 mol.) of 5-chloro-2-methylbenzothiazole and 25.1 g. (1 mol.) of p-sulfobenzylbromide were heated together at 160 C. in an oil bath for 12' hours. The brown viscous product was stirred with 50 cc. of acetone until crystalline, chilled to 0 C. and filtered. The product was washed on the filter with acetone and dried in vacuum over calcium chloride. The yield of gray hygroscopic solid was 9.1 g., 31 per cent. The

'p-sulfobenzyl bromide employed above can be prepared as follows. 86.0 g. (1 mol.) of p-toluenesul- Ionic acid and 400 g. of bromoform were heated to 140 C. in an oil bath. The mixture was stirred mechanically while 80 g. (1 mol.) of bromine was added dropwise over a period of 30 minutes. The mixture was heated and stirred 30 minutes longer, during which time the color of the bromine disappeared. The mixture was chilled to 0 C. the product collected on a filter, washed on the filter with cc. of bromoform and dried in a vacuum over potassium hydroxide sticks. The yield of hygroscopic gray solid product was 53.3 g., 42 per cent.

Example 16.2-methylbenzothiazole p-sulfobenzylbromide 12 This was prepared as in Example 15 from 16.4 g. (1 mol.) of 2-methylbenzothiazole and 27.6 g. (1 mol.) of p-sulfobenzyl bromide. The yield of brownish crystals was 4.8 g., 11 per cent.

Example 17.Lepz'dine p-sulfobenzylbromide This was prepared as in Example 15 from 14.3 g. (1 mol.) of lepidine and 25.1 g. (1 mol.) of p-sulfobenzyl bromide. The yield of yellow crystals was 6.6 g., 17 per cent.

Example 18.5-chloro-Z-methylbenzothiazole-B-sulfoethylbromide Br olnlsoan 18.35 g. (1 mol.) of 5-chloro-2-methylbenzothiazole and 18.9 g. (1 mol.) of 2-bromoethanesulfonic acid were heated over a flame until the temperature of the melt reached 220 C. The temperature was maintained between 200 and. 220 C. for 5 minutes, the mixture was cooled, crushed under acetone and chilled to 0C. The product was collected on a filter, washed on the filter with acetone and dried. The yield of pinkish crystals was 25.6 g., 69 per cent. The 2-bromoethanesulfonic acid employed above can be prepared as follows. g. (1 mol.) of finely powdered sodium 2-bromoethane sulfonate, 200 g. (1 mol. plus 10 per cent excess) of a 10 per cent solution of dry hydrogen chloride in absoluteethyl alcohol and 1000 cc. of absolute ethyl alcohol were stirred mechanically for one hour at room temperature. The precipitated sodium chloride was filtered off, washed on the filter with absolute ethyl alcohol and the filtrate and washings concentrated as far as possible on the steam bath using the water pump. The mixture was diluted with 500 cc. of dry benzene and again concentrated under reduced pressure. The residue was distilled slowly under as high a vacuum as possible. The product was a heavy oil which solidified to colorless crystals on cooling. The product boiled at to 162 C. at 2 mm. pressure. The yield of crude product was 89.8 g., 91 per cent and 65.0 g., 66 per cent after one distillation.

Example 19.2-methyl-a naphthothiazolep-sulfoethylbromide exam Example 20.2-methylbenzothiazoZe-csulfoethylbromz'de Br/ ciHisoarr This was prepared as in'Example from 14.9

g. (1 mol.) of 2-methylbenzothiazole and 18.9 g. (1 mol.) of 2-bromoethane sulfonic acid. The yield of gray crystals was 6.6 g., per cent.

Example 21.2,3,3-trimethylindolenineefi- .sulfoethylbromide responding carbalkoxyalkyl compounds. The following example illustrates further the preparation of .the cyclammonium carboxyalkyl quaternay salts by the hydrolysis of the corresponding cyclammonium carbalkoxyalkyl quaternary salts. Example 22.-Lepidine carboxymethobromide I Br 20.0 g. (1 mol.) of lepidine carbethoxymethobromide and 100 cc. of 48 per cent hydrobromic acid were boiled together under reflux for minutes. The mixture was concentrated nearly to dryness under reduced pressure and the sticky brown product dissolved in 100 cc. of absolute ethyl alcohol. The solution was chilled to 0 C., the product collected on a filter and washed on the filter with alcohol. The yield of tan crystals was 13.7 g., 75 per cent.

The cyclammonium carbalkoxyalkyl quaternary salts can be prepared by known methods.

4-phenylbenzothiazole is described in the copending application of Gertrude Van Zandt and Leslie G. S. Brooker, Serial No. 709,414, filed November 13, 1946 (now Unitedv States Patent 2,485,679, dated October 25, 1949), and can be prepared by oxidizing o-thioacetamidobiphenyl with potassium ferricyanide, in the presence of aqueous sodium hydroxide. Quaternary salts of 4-phenylbenzothiazole can be prepared by heating the base with p-sulfobenzyl bromide, fi-sulioethyl bromide, etc.

5-phenylbenzothiazole is described in the copending application of Gertrude Van Zandt and Leslie G. S. Brooker, Serial No. 711,816, filed November 22, 1946, and can be prepared by reducing bis (3-nitro-4-biphenylyl)disulfide with zinc and acetic acid and acetylating the reduction product with acetic anhydride. Quaternary salts of 5-phenylbenzothiazole can be prepared by heating the S-phenylbenzOthiazole withpsulfobenzyl bromide, fl-sulfoethyl bromide, etc.

In the preparation of photographic silver halide emulsions containing my newanhydro cyanine hydroxides, it is only necessary todisperse the dyes in the emulsions. Ordinarily this is advantageously accomplished by forming a water-soluble salt of the anhydro cyanine hydroxide and dissolving the water-soluble salt in water or methanol or a mixture of water and methanol, and dispersing the resulting solution in-the. emulsion. The salts are advantageously formed by adding to the anhydro cyanine hydroxide, wet with a little water, or methanol, an alkali metal hydroxide, or an amine, e. g. methylamine, ethylamine, ethanolamine, 'diethanolamine, triethanolamine, pyridine, N-methylpiperidine, n-propylamine, .n-butylamine, isopropylamine, ,B-ethoxyethylamine, etc. and taking up the salt which forms asuitable solvent, e. g. water, methanol or a mixture of water and methanol.

Sensitization by means of my new anhydrocyanine hydroxides and-their salt forms -is primarily directed to the ordinarily employed gelatino-silver-halide developing-out emulsions, e. g. gelatino silver-chloride, -chlorobromide, chlorobromoiodide, -bromide, and brom'o1iodide emulsions. The anhydrocyanine. hydroxides 01 their salts are advantageously added to the washed, finished emulsions and should be uniformly distributed throughout the emulsions.

The concentration of 'the anhydrocyanine hydroxides or their salts can vary w-idely,-e. g. from about 5 to about mg. per liter of flowable emulsion. The concentration will vary according to the type of light sensitive material and according to the efiect desired. The suitable and most economical concentration 'ior'anygiven emulsion will be apparent to those skilled in the art, upon making the ordinary tests and observations customarily used in the art of emulsion making. To prepare .a gelatino-silverhalide emulsion sensitized with one or more of my new anhydro cyanine hydroxides, the following procedure is satisfactory: a quantity of the anhydro cyanine hydroxide in salt form is -.dissolved in water or methyl alcohol or a mixture of water and methyl alcohol, and a volume of the solution containing from 5 to 100 mg. of the salt of the anhydro cyanine hydroxide is slowly added to about 1000 cc. of a gelatino-silver-halide emulsion with stirring. Stirring is continued until the salt of the anhydro cyanine hydroxide is uniformly dispersed. With the more powerful of my new anhydro cyanine hydroxides, 10 to 50 mg. of anhydro cyanine hydroxide or salt thereof per 1000 cc. of emulsion sufiice to produce the maximum sensitizing effect with the ordinary gelatizno-silver-halide emulsions. The above statements are only illustrative and. are not to be understood as limiting my invention in any sense, as it will be apparent that my new anhydro cyanine hydroxides and salts thereof can be incorporated by other methods in many of the photographic emulsions customarily employed in the art, such, for instance, as by bathing a plate or film upon which an emulsion is coated, in a solution of the anhydro cyanine hydroxide (or its salt form) in an appropriate solvent, although such a method is ordinarily. not to be preferred. The emulsion claims are intended to cover any combination of these new anhydro cyanine hydroxides (or salts thereof) with a photographic silver halide emulsion whereby, the anhydro cythe quinoline series, and the metal and am- 16 anine hydroxides or salts thereof exert a sensi- 5. The anhydro cyanine hydroxides represented tizing effect on the emulsion. by the following general formula:

What I claim as my invention and desire to be secured by Letters Patent of the United States is: 1

z s l. The anhydro cyanine hydroxides which are 5 r represented by the following general formula: wherein Z represents the non-metallic atoms t g a J necessary to complete a heterocyclic nucleus of the benzothiazole series and Z1 represents the s01- non-metallic atoms necessary to complete a wherein d and 11, a h represents a positive i heterocyclic nucleus of the quinoline series. teger of from 1 to 2, m represents a positive in- The anhydro ya yd x d r pr s n ed teger of from 1 to 3, L represents a methlne group, y the ll win eral formula:

I Y Z\\ CZHS Z HOaSCHzCH2l 1 b=0H-l5=CH-==l$GHz-GH1SOr R represents an alkyl group, D represents a diwherein Z represents the non-metallic atoms valent hydrocarbon radical, and Z and Z1 each necessary to complete a heterocyclic nucleus of represents the non-metallic atoms necessary to the benzothiazole series.

complete a heterocyclic nucleus selected from 7. The anhydro cyanine hydroxides represented the group consisting of heterocyclic nuclei of the by the following general formula:

HoocoH,-orrr-N' \O=OH(IJ=CHG fi-CHi-CHfl-SOJ' benzothiazole series and heterocyclic nuclei of wherein Z represents the non-metallic atoms 2 necessary to complete a heterocyclic nucleus of monium salt forms of said anhydro cyanine th benzothiazole series. hydroxides. 8. The anhydro cyanine hydroxide represented 2. The anhydro cyanine hydroxide represented by the following formula: by the following formula:

S S\ S O O=GHC=GH--O -[I is m CuHs- (l; l

C CH- is HqCHzSOr 3. The anhydro cyanine hydroxide represented 9. The anhydro cyanine hydroxide represented by the following formula:

by the following formula: 5 s

/S S\ \C=CHC=CH C/ 01- N/ in 01 01 01 \N/ (112115 2H4S 0 3H (JQH4S O r Hz-CHPSOzH (IJH2-CHQ'SOF ROBERT E SPRAGUE' 4. The anhydro cyanine hydroxide represented REFERENCES CITED by the following formula: The following references are of record in the S\ /S file of this patent: [I C=GH C=CH C UNITED STATES PATENTS 01-- Number Name Date fi 2,430,558 Carol] Nov. 11, 1947 ROBERT H. SPRAGUE Certificate of Correction Patent No. 2,503,776 April 11, 1950 It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 3, line 51, for condensating read condensing; column 5, line 62, for 2-(-anilino read 2-(4-aniltno; column 15, lines 49 to 53 inclusive, for the right-hand portion of the formula reading 0 read 0 and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 18th day of July, A. D. 1950.

[SEAL] JOE E. DANIELS,

Assistant Commissioner of Patents. 

1. THE ANHYDRO CYANINE HYDROXIDES WHICH ARE REPRESENTED BY THE FOLLOWING GENERAL FORMULA: 